Some Specific Air Perm Fabrics (NeoShell, eVent, Dry.Q Elite…)
A couple of air perm fabrics are already on the market today. Polartec NeoShell was the first membrane to focus its marketing on the fact that it is air permeable, though eVent has been around a bit longer and is also air permeable. Mountain Hardwear’s Dry.Q Elite is also notable (though it is likely just rebranded eVent). Marmot now has proprietary air perms as well, Nano Pro and Nano Pro Membrane.
NeoShell uses a proprietary process to create a porous PU membrane. PU is naturally oleophobic (repels oils), so there is less danger of fouling, and it’s also very stable over time and in different environments (temperature, humidity, etc.). Though Polartec will not divulge how they make their laminates, by the look of some of Polartec’s promotional material, it seems to be some sort of PU microfiber mesh. I imagine the manufacturing process looks something like making cotton candy (i.e., an electro spinning process, though I’m walking in the realm of pure conjecture here).
eVent uses an expanded polytetrafluoroethylene membrane (ePTFE), the same material that Gore uses on the outer layer of their membranes. Instead of protecting the ePTFE with a thin PU layer, however, eVent uses a proprietary oleophobic coating that keeps the ePTFE from fouling over time. Like Polartec, eVent is very tight lipped about this process and the materials at work.
In the spirit of further conjecture, I imagine that eVent applies their oleophobic coating using a chemical vapor deposition process, and that the coating contains fluorocarbon chemistry. (Again, though, pure conjecture.)
Nano Pro & Nano Pro Membrane
New from Marmot this year is a technology called Nano Pro. Entering the rather small arena of air perms as an OEM and a fabric/laminate producer is allowing Marmot to out-price just about every other air perm on the market. We aren’t ready to publish a review of a jacket made with Nano Pro yet, but so far the response around the industry been very positive.
Marmot is using the technology in two different 2.5 layer constructions. “Nano Pro” is the cheaper of the two and involves a micro porus, air permeable PU material that has been applied (likely via some painting or spraying process) to the underside of a face fabric.
“Nano Pro Membrane,” on the other hand, features a standard laminate construction in which a porus, air permeable PU membrane “film” is built separate from the face fabric and then applied to the face fabric (like wallpaper).
Marmot has published air permeability rates for these two new constructions and the laminated Nano Pro Membrane boasts significantly higher breathability numbers than the coated Nano Pro.
In any case, these manufacturing processes and materials in the air permeable membranes generally aren’t a huge selling point to the average consumer. The real take-home here is that Nano Pro and these other new membranes allow for a controlled amount of air permeability while still being protected from fouling by sweat, dirt, and oils.
Gore-Tex Active Shell & Gore-Tex Pro (…and Air Permeability…)
So far, Gore-Tex has yet to market a fabric as “air permeable,” but they do have two major membranes that are big players in the current outerwear market: Active Shell (their most breathable material) and their new Pro membrane (which offers the highest level of protection of any Gore fabric).
Active Shell increases the breathability of the membrane over traditional Gore-Tex or Gore-Tex Pro by utilizing a high-temperature, high-pressure process to physically integrate the fabric’s tricot liner to the protective PU layer on the inside of the ePTFE membrane. This brings the hydrophilic tricot liner significantly closer to the ePTFE membrane, thus increasing breathability.
Gore-Tex is still able to keep the PU layer as thick as it needs to be (either for protection of the ePTFE, or because of manufacturing limitations—it’s hard to say which dictates the minimum PU thickness) while making it act much thinner than it actually is because the tricot liner is physically integrated with the PU layer.
Gore-Tex Pro (not to be confused with Gore-Tex Pro Shell, the previous generation of Gore’s high-end WPB fabric) is Gore’s latest top-tier laminate, first featured in outerwear products in the fall of 2013.
Gore-Tex Pro’s ePTFE membrane is actually made up of three different layers. Two ePTFE layers are bonded to each other in a high-temperature and high-pressure process (likely similar to how Active Shell’s tricot liner is bonded to the inner side of its membrane). Between them is a higher-density ePTFE material. Together these three ePTFE components make up the Gore-Tex Pro membrane.
It appears that the Gore Pro membrane is protected from fouling via this multi-layer ePTFE structure (as Gore Pro now uses no polyurethane “PU” protective layer). The inner layer of ePTFE acts as a sacrificial layer, absorbing all of the gunk (sweat, dirt, ions, etc.) that would otherwise eventually foul the rest of the membrane, compromising its waterproofing capabilities. The higher-density ePTFE material at the interface of the two layers is enough to keep that gunk away from the second ePTFE membrane.
Here’s my theory about Gore-Tex Pro:
Gore-Tex realizes that their current technologies will not be able to compete with air perms as far as breathability goes.
But they can’t really copy eVent or Polartec, because the idea of air permeability is seemingly in direct conflict with Gore’s promise of 100% waterproof fabrics.
The membrane that Gore has created is just ambiguous enough that it doesn’t look air permeable. And that’s probably enough. Especially considering that Gore-Tex Pro preforms really well.
My hunch is that Gore-Tex Pro is actually slightly air permeable—not as much as eVent or NeoShell—but enough to substantiate Gore’s claim of 36% increased breathability over previous Pro Shell generations. Of course, Gore would never admit this to be true, and, again, I am purely speculating that Gore-Tex Pro is air permeable…
So while you might not be ready to have conversations about airflow rates and pressure drops across membranes, or likely hear about them on the chairlift (unless you’re on the chair with me), it should be clear that the world of outwear is changing in a big way.
We are particularly impressed with these new air permeable fabrics. They do a great job keeping you dry and can significantly increase your comfort in the mountains, allowing you to recreate harder and longer.
In reviewing different pieces of outerwear, we’ve had a chance to test most of the waterproof / breathable fabrics discussed in this article in the mountains. To read about their real-world performance in the jackets we’ve tested, see the following reviews:
Mountain Equipment Centurion and Tupilak jackets (Polartec NeoShell and Gore-Tex Pro, respectively)
Rab Viper (eVent DVL)